The company has received four complaints about lithium ion batteries overheating and damaging ThinkPad laptops when the batteries were dropped or otherwise struck on the corner. The batteries in question are the extended, nine-cell battery, which Lenovo sells as an upgrade option on three ThinkPad lines: the R Series (R60 and R60e), the T Series (T60 and T60p), and the Z Series (Z60m, Z61e, Z61m, and Z61p). Manufactured by Sanyo, the recalled 9-cell batteries were sold between November 2005 and February 2007 and have the part number FRU P/N 92P1131, which can be found on the battery label.

This is a different flaw than the internal battery cell defect that caused last year's Sony battery recall. While no injuries have been reported aside from minor eye irritation in one case, the batteries do pose a fire hazard.

Lenovo instructed its customers to stop using the recalled batteries and contact the company for additional information and to receive a free replacement battery. You can call 800-426-7378 or check this page on Lenovo's site.